1. Field of the Invention
The present invention relates to an auto-document feeder for a peripheral device. More particularly, the present invention relates to a document scanner having duplex feeding capability.
2. Description of the Related Art
Printers, scanners, copiers, facsimile devices, and combinations thereof, including but not limited to, all-in-one or multi-function peripherals are being designed more frequently to perform duplex document feeding. Such feeding functionality allows for documents to be scanned from and/or printed on both sides of the document.
Inclusion of duplexing functionality is known within business class peripherals, which are typically of a larger size and therefore able to accommodate structure to perform duplex functions. However one problem with implementing this functionality into consumer devices is the limited product size of consumer peripherals. When including duplexing capability into a consumer peripheral, the device must be large enough to accommodate a media sheet of suitable size for feeding both through a simplex path and a duplex path.
In order to accommodate duplexing functionality into a consumer sized auto-document feeder, a duplexing path has been designed to be shorter than the length of a media sheet. In this feedpath configuration, a media leading edge and trailing edge may pass through a single nip at the same time. It is desirable that such simultaneous passing of the leading edge and trailing edge of a media sheet through a single nip not cause scanning or feeding defects which lead to decreased scan quality output from the device or print feed quality which is decreased. In addition, it is desirable that a duplex feeding device have the capability of feeding various media sizes. Some prior art duplex devices rely on gear timing to in order allow duplex feeding. However, where functions are merely timed during feeding control is lost and ability to feed multiple media sizes is inhibited.